a) Filed of the Invention
The present invention relates to an expanding sleeve fixture and more particularly to a push-type expanding fixture to secure a work-piece to a rotatable machine without inducing compression forces.
b) Background of the Related Art
Numerous devices have been developed to hold and center work-pieces. These devices include collapsible-type mechanisms wherein a collet or chuck tightens onto a portion of a work-piece, and expansible-type mechanisms wherein an expandable collet or chuck member is inserted into an internal bore or opening of a work-piece and expanded therein to grip or hold the work-piece on the expandable member. However, previously known devices for holding and centering work-pieces have proven deficient in various respects. Particularly, the procedures for attaching and detaching the work-piece from the devices are relatively time consuming and complex, and can require the tightening and loosening of multiple parts with special chuck tools in order to attach and detach the work-pieces, which adds to the time and cost ultimately required for preparation of machined parts. Another problem is that many devices are complex in design and include numerous movable parts which are subject to wear and failure. A further drawback is that prior art devices induce a compression force on the work-piece when attempting to expand an internal mandrel. The drawbacks of the prior art hinder the effective use of currently available holding devices with the advanced machine tools used in modern manufacturing operations. Moreover, the prior art devices do not facilitate the holding of a side gear to facilitate a roll forming process.
Accordingly, there is a need for a push-type expanding mandrel apparatus which quickly and releasably holds a work-piece, which does not induce a compression force on the work-piece, and is suitable for use with high precision machine tools. The present invention overcomes the drawbacks of the prior art and other related art.
The present invention alleviates the drawbacks of the related art. A push-type expandable fixture is provided to secure a work-piece to a rotatable machine. Two rotatable portions of the machine are capable of longitudinally moving in toward each other. An expandable sleeve is inserted within a bore of a hollow work-piece. The work-piece together with the expandable sleeve is disposed on a pair of wedge members which are in turn secured to a first rotatable portion of the machine. The second wedge member is longitudinally displaceable relative to the second wedge member. The pair of wedge members together extend through the work-piece to engage the second rotatable portion of the machine. The expandable sleeve has tapered surfaces extending radially inward and converging toward a radial inward most portion intermediate the sleeve. As the first and second rotatable portions of the machine are brought toward one another, the sleeve is forced to radially expand and thus firmly grip the work piece. The arrangement provides the ability to firmly secure a work-piece to a rotatable machine tool by a simply push-type action without the need to induce compression forces on the work-piece. The arrangement is especially suited for securing a differential side gear to a rotatable machine tool to allow roll forming of the side gear""s bevel gear teeth.
Other objects and advantages of the invention will become apparent from a study of the following specification when viewed in light of the accompanying drawings.